JP2018059019A - Molding and method for producing molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding that does not allow moisture permeation and has excellent mechanical strength.SOLUTION: A molding is molded from a polyamide resin composition that has a semi-aromatic polyamide resin, and a fiber with a number average fiber length of more than 300 μm, wherein, in the semi-aromatic polyamide resin, a terminal carboxyl group concentration is higher than a terminal amino group concentration. There is also provided a method for producing the molding.SELECTED DRAWING: None

Description

  The present invention relates to a molded article and a method for producing the molded article. In particular, the present invention relates to a molded product suitable for a camera component mounted on an automobile and a method for manufacturing the molded product.

A polyamide resin, which is a typical engineering plastic, is easy to process, and is excellent in mechanical properties, electrical properties, heat resistance, and other physical and chemical properties. For this reason, it is widely used for vehicle parts, electrical and electronic equipment parts, and other precision equipment parts.
For example, Patent Literature 1 contains 60 to 100 mol% of a dicarboxylic acid unit containing 60 to 100 mol% of a terephthalic acid unit and 1,9-diaminononane unit and / or 2-methyl-1,8-diaminooctane unit. The polyamide (A) having a diamine unit and the fibrous reinforcing material (B) are melt-kneaded, and the content of the polyamide (A) is 50 to 80% by mass, and the content of the fibrous reinforcing material (B) Is a barrel or holder of a camera module formed by molding a polyamide composition having a mass of 20 to 50% by mass, wherein the average length of the fibrous reinforcing material (B) before melt kneading is 300 μm or less. A barrel or holder is disclosed.

JP 2010-286544 A

  When this inventor examined about the said patent document 1, in the said patent document 1, although the fibrous filler was mix | blended, it turned out that mechanical strength is inadequate. In addition, precision machine parts such as camera parts are also required to be less permeable to moisture. The object of the present invention is to provide a molded article that is excellent in mechanical strength and hardly permeates moisture.

As a result of investigation by the present inventors based on the above problems, a semi-aromatic polyamide resin having a terminal carboxyl group concentration higher than the terminal amino group concentration is used, and the number average fiber length is molded from a fiber exceeding 300 μm. It has been found that by improving the adhesion between the semi-aromatic polyamide resin and the fiber, improving the mechanical strength, and making it difficult to transmit moisture, the present invention has been completed. .
Specifically, the above problem has been solved by the following means <1>, preferably <2> to <15>.
<1> Molded from a polyamide resin composition containing a semi-aromatic polyamide resin and a fiber having a number average fiber length exceeding 300 μm, wherein the terminal aromatic group concentration of the semi-aromatic polyamide resin is higher than the terminal amino group concentration Molding.
<2> The molded article according to <1>, wherein the fiber is at least one selected from carbon fiber and glass fiber.
<3> The molded article according to <1> or <2>, wherein the fiber is treated with at least one of a surface treatment agent and a sizing agent.
<4> The molded article according to any one of <1> to <3>, wherein the number average fiber length of the fibers is 1.0 mm to 6.0 mm.
<5> The molded article according to any one of <1> to <4>, wherein the difference between the terminal carboxyl group concentration and the terminal amino group concentration is 40 to 100 μeq / g.
<6> The semi-aromatic polyamide resin is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and is derived from dicarboxylic acid. The molded article according to any one of <1> to <5>, wherein 70 mol% or more of the units are derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.
<7> The semi-aromatic polyamide resin is composed of a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, and 70 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine, and is derived from a dicarboxylic acid. The molded article according to any one of <1> to <5>, wherein 70 mol% or more of the units are derived from adipic acid.
<8> The molded article according to any one of <1> to <7>, further including a black colorant.
<9> The molded article according to any one of <1> to <8>, further including talc.
<10> Further, a black colorant and talc are included, and the mass ratio of the black colorant to talc (black colorant / talc) in the molded product is 1.5 to 2.5, <1> to <7 > The molded product according to any one of
<11> The molded product according to any one of <1> to <10>, which is an injection molded product.
<12> The molded product according to any one of <1> to <11>, which is a camera component.
<13> The molded product according to <12>, wherein the maximum length of the camera component is 15 to 40 mm.
<14> The molded article according to <12> or <13>, in which the camera component includes a member derived from the polyamide resin composition, and a ratio of the member is 1 to 99% by mass.
<15> injection molding a polyamide resin composition comprising a semi-aromatic polyamide resin and a fiber having a number average fiber length exceeding 300 μm, wherein the terminal aromatic group concentration of the semi-aromatic polyamide resin is higher than the terminal amino group concentration The manufacturing method of the molded article as described in any one of <1>-<14> including this.

  According to the present invention, it is possible to provide a molded article that has excellent mechanical strength and is difficult to transmit moisture.

It is the schematic which shows the measuring apparatus of a moisture permeability coefficient.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

The molded article of the present invention comprises a semi-aromatic polyamide resin and fibers having a number average fiber length exceeding 300 μm, and the terminal aromatic group concentration of the semi-aromatic polyamide resin is higher than the terminal amino group concentration. It is a molded article formed from
By using a semi-aromatic polyamide resin having a terminal carboxyl group concentration higher than the terminal amino group concentration, and using a fiber having a number average fiber length exceeding 300 μm, the adhesion of the semi-aromatic polyamide resin to the fibers is improved, A molded article having high mechanical strength can be obtained. Furthermore, a molded product that hardly permeates moisture is obtained.

<Semi-aromatic polyamide resin>
The molded article of the present invention contains a semi-aromatic polyamide resin.
Here, the semi-aromatic polyamide resin is composed of a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, and 30 to 70 mol% of the total structural unit of the structural unit derived from the diamine and the structural unit derived from the dicarboxylic acid. It is a structural unit containing an aromatic ring, and 40 to 60 mol% of the total structural unit of the structural unit derived from diamine and the structural unit derived from dicarboxylic acid is preferably a structural unit containing an aromatic ring.

The semi-aromatic polyamide resin used in the present invention has a terminal carboxyl group concentration higher than a terminal amino group concentration. By setting it as such a structure, the adhesiveness of a fiber and a semi-aromatic polyamide resin can be improved.
The difference between the terminal carboxyl group concentration and the terminal amino group concentration in the present invention is preferably 40 to 100 μequivalent / g. By setting it as such a range, adhesiveness with a fiber can be improved more.
The difference between the terminal carboxyl group concentration and the terminal amino group concentration has a lower limit of preferably 45 μequivalent / g or more, and more preferably 47 μequivalent / g or more. The upper limit of the difference between the terminal carboxyl group concentration and the terminal amino group concentration is preferably 90 μeq / g or less, more preferably 80 μeq / g or less, and 70 μeq / g or less. More preferably, it is 65 μequivalent / g or less, and more preferably 55 μequivalent / g or less.
The semi-aromatic polyamide resin used in the present invention preferably has a terminal amino group concentration ([NH ₂ ]) of less than 100 μequivalent / g, more preferably 5 to 75 μequivalent / g, and still more preferably 10 to 60 μequivalent / g. g, more preferably 20-50 μeq / g. The semi-aromatic polyamide resin used in the present invention has a terminal carboxyl group concentration ([COOH]) of preferably less than 150 μequivalent / g, more preferably 20 to 120 μequivalent / g, still more preferably 40 to 110 μequivalent / g. g, More preferably, it is 50-100 microequivalent / g, More preferably, it is 75-100 microequivalent / g.
Furthermore, the ratio of the terminal amino group concentration to the terminal carboxyl group concentration ([NH ₂ ] / [COOH]) is preferably 0.7 or less, more preferably 0.6 or less, and even more preferably 0.5 or less. When the ratio is greater than 0.7, it may be difficult to control the molecular weight when polymerizing the semi-aromatic polyamide resin. The lower limit value of the ratio of the terminal amino group concentration to the terminal carboxyl group concentration ([NH ₂ ] / [COOH]) is not particularly defined, but may be 0.2 or more, for example.
The terminal amino group concentration and the terminal carboxyl group concentration of the semi-aromatic polyamide resin are measured according to the method described in Examples described later. When the devices described in the examples cannot be obtained due to the out-of-print version or the like, other devices having equivalent performance can be used. Hereinafter, the same applies to other measurement methods.

Examples of the semi-aromatic polyamide resin used in the present invention include polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyamide 66 / 6T, polyxylylene adipamide, and polyxylylenese. Examples include bacamide, polyxylylene decamide, polyamide 9T, polyamide 9MT, and polyamide 6I / 6T.
In addition, semi-aromatic polyamide resins described in paragraphs 0020 to 0058 of JP-A No. 2006-138163 are preferably used.

  Among the semi-aromatic polyamide resins as described above, from the viewpoint of moldability and heat resistance, it is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is xylylene range. A semi-aromatic polyamide resin (hereinafter referred to as “XD-based polyamide”) derived from an amine, wherein 70 mol% or more of a structural unit derived from a dicarboxylic acid is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. Are preferred).

The XD-based polyamide is derived from xylylenediamine in which 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more of the structural unit derived from diamine is derived from dicarboxylic acid. 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more of the structural unit is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. To do.
The xylylenediamine is preferably paraxylylenediamine, metaxylylenediamine, or a mixture of both, and more preferably contains at least metaxylylenediamine.

Examples of diamines other than metaxylylenediamine and paraxylylenediamine that can be used as the raw material diamine component of the XD polyamide include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, and octanediamine. Aliphatic diamines such as methylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bis (amino Methyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis ( -Aminocyclohexyl) propane, bis (aminomethyl) decalin, alicyclic diamines such as bis (aminomethyl) tricyclodecane, bis (4-aminophenyl) ether, paraphenylenediamine, fragrances such as bis (aminomethyl) naphthalene Examples include diamines having a ring, and one kind or a mixture of two or more kinds can be used.
When a diamine other than xylylenediamine is used as the diamine component, it is preferably less than 20 mol% of the structural unit derived from diamine, and more preferably 10 mol% or less.

  Preferred examples of the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms to be used as the raw material dicarboxylic acid component of the semi-aromatic polyamide resin include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, Aliphatic dicarboxylic acids such as adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid can be exemplified, and one or a mixture of two or more types can be used. Therefore, adipic acid or sebacic acid is preferable, and adipic acid is more preferable.

  Examples of the dicarboxylic acid component other than the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid and orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,3 -Naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalene Examples thereof include naphthalenedicarboxylic acids such as isomers such as dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and one kind or a mixture of two or more kinds can be used. When using a dicarboxylic acid component other than an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, it is preferably less than 20 mol% of the structural unit derived from the dicarboxylic acid, and preferably 10 mol% or less. More preferred.

  The semi-aromatic polyamide resin is composed mainly of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, but does not completely exclude other structural units. Ε-caprolactam and laurolactam Needless to say, it may contain structural units derived from aliphatic aminocarboxylic acids such as lactams such as aminocaproic acid and aminoundecanoic acid. In the present invention, the total of diamine-derived structural units and dicarboxylic acid-derived structural units in the semi-aromatic polyamide resin preferably occupies 90% or more, more preferably 95% or more of all structural units.

The melting point of the semi-aromatic polyamide resin is preferably 150 to 350 ° C, more preferably 180 to 330 ° C, and further preferably 200 to 300 ° C.
Moreover, 50-150 degreeC is preferable, as for the glass transition temperature of a semi-aromatic polyamide resin, 55-120 degreeC is more preferable, Especially preferably, it is 60-100 degreeC. Within this range, the heat resistance of the molded product tends to be better.

The melting point of the semi-aromatic polyamide resin is measured as the temperature at the peak top of the endothermic peak at the time of temperature rise observed by the DSC (differential scanning calorimetry) method. The glass transition temperature of the semi-aromatic polyamide resin is measured as a peak top temperature which is measured by heating again after the semi-aromatic polyamide resin is heated and melted to eliminate the influence of the thermal history on the crystallinity.
Specifically, using a DSC measuring device, the amount of the semi-aromatic polyamide resin as a sample was about 1 mg, nitrogen was flowed at 30 mL / min as the atmospheric gas, and the temperature rising rate was 10 ° C./min. The melting point is determined from the temperature at the peak top of the endothermic peak observed when melting from room temperature to the expected melting point or higher. Next, the melted semi-aromatic polyamide resin is quenched with dry ice, and the temperature is raised again to a temperature equal to or higher than the melting point at a rate of 10 ° C./min, and the glass transition temperature is obtained. Examples of the DSC measuring instrument include DSC-60 manufactured by SHIMADZU CORPORATION.

  The semi-aromatic polyamide resin preferably has a number average molecular weight (Mn) of 6,000 to 30,000, more preferably 8,000 to 28,000, and further preferably 9,000 to 26,000. More preferably, it is 10,000-24,000, More preferably, it is 11,000-22,000. Within such a range, the heat resistance, elastic modulus, dimensional stability, and moldability become better.

In addition, the number average molecular weight (Mn) here means the terminal amino group concentration [NH ₂ ] (μ equivalent / g) and the terminal carboxyl group concentration [COOH] (μ equivalent / g) of the semi-aromatic polyamide resin, It is calculated by the following formula.
Number average molecular weight (Mn) = 2,000,000 / ([COOH] + [NH ₂ ])

The semi-aromatic polyamide resin preferably has a molecular weight distribution (weight average molecular weight / number average molecular weight (Mw / Mn)) of 1.8 to 3.1. The molecular weight distribution is more preferably 1.9 to 3.0, still more preferably 2.0 to 2.9. By setting the molecular weight distribution in such a range, a three-dimensional structure excellent in mechanical properties tends to be obtained.
The molecular weight distribution of the semi-aromatic polyamide resin can be adjusted, for example, by appropriately selecting the polymerization reaction conditions such as initiator, catalyst species, amount, reaction temperature, pressure, and time used during polymerization. It can also be adjusted by mixing a plurality of types of semi-aromatic polyamide resins having different average molecular weights obtained under different polymerization conditions or by separately precipitating semi-aromatic polyamide resins after polymerization.

  The molecular weight distribution can be determined by GPC measurement. Specifically, using “HLC-8320GPC” manufactured by Tosoh Corporation as a device and two “TSK gel Super HM-H” manufactured by Tosoh Corporation as columns, eluent As follows: Hexafluoroisopropanol (HFIP) having a sodium trifluoroacetate concentration of 10 mmol / L, a resin concentration of 0.02% by mass, a column temperature of 40 ° C., a flow rate of 0.3 mL / min, and a refractive index detector (RI). The standard polymethyl methacrylate (PMMA) conversion value can be obtained. A calibration curve is prepared by dissolving 6 levels of PMMA in HFIP.

The lower limit of the content of the semi-aromatic polyamide resin in the molded product of the present invention is preferably 25% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more, The content is more preferably 50% by mass or more, and further preferably 55% by mass or more. The upper limit of the content is preferably 75% by mass or less, and more preferably 70% by mass or less.
The molded article of the present invention may contain only one type of semi-aromatic polyamide resin, or may contain two or more types. When 2 or more types are included, the total amount is preferably within the above range.

  In the molded product of the present invention, it is preferable that the total of the semi-aromatic polyamide resin and the filler containing fibers described later occupy 90% by mass or more.

<Other polyamide resins>
The molded article of the present invention may contain one or more polyamide resins other than the semi-aromatic polyamide resin. Examples of such a polyamide resin include polyamide 4, polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 610, polyamide 612, and the like.
Of course, in this invention, the structure which does not contain these other polyamide resins may be sufficient. “Substantially free” means that the content of the other polyamide resin is 2% by mass or less of the content of the semi-aromatic polyamide resin contained in the molded article of the present invention, and preferably 1% by mass or less. 0.1 mass% or less is more preferable.

<Fiber>
The molded article of the present invention contains fibers.
The fiber is not particularly defined as long as the number average fiber length exceeds 300 μm, and a known fiber can be used. The lower limit of the number average fiber length of the fibers is preferably 500 μm or more, more preferably 1.0 mm or more, further preferably 2.0 mm or more, and further preferably 3.0 mm or more. The upper limit of the number average fiber length of the fibers is preferably 6.0 mm or less, more preferably 5.0 mm or less, and even more preferably 4.0 mm or less.

  The type of fiber is not particularly limited, but inorganic fibers such as glass fiber, carbon fiber, plant fiber (including Kenaf, bamboo fiber, etc.), alumina fiber, boron fiber, ceramic fiber, metal fiber (steel fiber, etc.) And organic fibers such as aramid fibers, polyoxymethylene fibers, polyparaphenylene benzobisoxazole fibers, and ultrahigh molecular weight polyethylene fibers. Among these, at least one selected from carbon fibers, aramid fibers and glass fibers is preferable, at least one selected from carbon fibers and glass fibers is more preferable, and at least selected from glass fibers. More preferably, it is one type.

  A glass fiber has glass compositions, such as A glass, C glass, E glass, and S glass, and E glass (an alkali free glass) is especially preferable. The glass fiber may contain only 1 type and may contain 2 or more types.

The fiber used in the present invention may be a single fiber or a plurality of single fibers twisted together.
The fibers used in the present invention are preferably treated with at least one of a surface treatment agent and a sizing agent. Examples of the surface treating agent include coupling agents such as a silane coupling agent, a titanium coupling agent, and an aluminate coupling agent. Examples of the sizing agent include epoxy compounds, urethane compounds, carboxylic acid compounds, urethane / maleic acid modified compounds, and urethane / amine modified compounds. By using the surface treatment agent and / or the sizing agent, the adhesion with the semi-aromatic polyamide resin can be further improved, and the mechanical strength of the molded product of the present invention can be further improved.

  The lower limit of the fiber content used in the present invention is preferably 25% by mass or more, more preferably 26% by mass or more, and further preferably 28% by mass or more. The upper limit of the content is preferably 75% by mass or less, more preferably 65% by mass or less, further preferably 55% by mass or less, and further preferably 45% by mass or less, It is still more preferable that it is 35 mass% or less. The molded article of the present invention may contain only one type of fiber, or may contain two or more types. When 2 or more types are included, the total amount is preferably within the above range.

<Other fillers>
The molded article of the present invention may contain other fillers in addition to the fibers having the number average fiber length exceeding 300 μm. Examples of the other filler include fibers having a number average fiber length of 300 μm or less.
In the molded product of the present invention, the content of the filler other than the fibers having the number average fiber length exceeding 300 μm is preferably 10% by mass or less of the fibers having the number average fiber length exceeding 300 μm. % Or less, more preferably 3% by mass or less, and still more preferably 1% by mass or less. By setting it as such a range, it exists in the tendency for the effect of this invention to be exhibited more effectively.

<Black colorant>
The molded article of the present invention may contain a black colorant. By blending a black colorant, a molded article having excellent light shielding properties can be obtained.
Examples of the black colorant used in the present invention include carbon black. The details of carbon black can be referred to the description in paragraph 0021 of JP2011-57977A, the contents of which are incorporated herein.
Moreover, when mix | blending black colorants, such as carbon black, with the molded article of this invention, it is preferable to knead | mix with a semi-aromatic polyamide resin after forming a masterbatch. For details of the master batch, the description in paragraphs 0038 to 0042 of JP2011-57977A can be referred to, and the contents thereof are incorporated in the present specification. Furthermore, when manufacturing the molded article of the present invention by laser welding, it is also preferable to use a light-transmitting black colorant. The light-transmitting black colorant is a colorant having a high transmittance in the range of the wavelength of laser light to be irradiated, for example, in the range of wavelengths of 800 nm to 1064 nm. Specific examples include nigrosine, naphthalocyanine, aniline black, phthalocyanine, porphyrin, perylene, perinone, quaterylene, azo dye, anthraquinone, squaric acid derivative, and immonium dye. Examples of commercially available products include e-Bind ACW-9871 and e-BIND LTW-8731H, which are colorants manufactured by Orient Chemical Industries.
When the molded article of the present invention contains a black colorant, the content thereof is preferably 0.1 to 10 parts by mass, and 0.5 to 8 parts by mass with respect to 100 parts by mass of the semi-aromatic polyamide resin. More preferably, 1-6 mass parts is further more preferable.
The molded article of the present invention may contain only one type of black colorant, or may contain two or more types. When 2 or more types are included, the total amount is preferably within the above range.

<Talc>
The molded article of the present invention may contain talc. In the present invention, crystallization can be promoted by blending talc.
The blending amount of talc in the molded product of the present invention is preferably 0.05 to 20% by mass, more preferably 0.1 to 10% by mass, and 0.15 to 5% with respect to the molded product. It is more preferable that it is mass%, and it is still more preferable that it is 0.2-2 mass%. Only one type of talc may be used, or two or more types may be used in combination. In the case of two or more types, the total amount is preferably within the above range.

  In the present invention, in particular, a black colorant and talc are included, and the mass ratio of the black colorant to talc (black colorant / talc) in the molded product is preferably 1.5 to 2.5. It is more preferable that it is 8-2.2. By setting it as such a range, the molded article excellent in light-shielding property is obtained, promoting crystallization of a semi-aromatic polyamide resin.

<Release agent>
The molded article of the present invention may contain a release agent. Examples of the releasing agent include aliphatic carboxylic acids, salts of aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, and polysiloxane silicone oil. Etc.

  Examples of the aliphatic carboxylic acid include saturated or unsaturated aliphatic monovalent, divalent or trivalent carboxylic acid. Here, the aliphatic carboxylic acid includes alicyclic carboxylic acid. Among these, preferable aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms are more preferable. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, mellicic acid, tetratriacontanoic acid, montanic acid, adipine Examples include acids and azelaic acid. Examples of the salt of the aliphatic carboxylic acid include sodium salt, potassium salt, calcium salt, and magnesium salt.

  As aliphatic carboxylic acid in ester of aliphatic carboxylic acid and alcohol, the same thing as the said aliphatic carboxylic acid can be used, for example. On the other hand, examples of the alcohol include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, monohydric or polyvalent saturated alcohols having 30 or less carbon atoms are preferable, and aliphatic or alicyclic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or less carbon atoms are more preferable.

  Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol, and the like. Is mentioned.

  Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture based on myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate Examples thereof include rate, glycerol distearate, glycerol tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate and the like.

Examples of the aliphatic hydrocarbon having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomer having 3 to 12 carbon atoms. Here, the aliphatic hydrocarbon includes alicyclic hydrocarbons. The number average molecular weight of the aliphatic hydrocarbon is preferably 5,000 or less.
Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferable, and paraffin wax and polyethylene wax are more preferable.

  When the molded product of the present invention contains a release agent, the content of the release agent is preferably 0.001 to 2% by mass, and 0.01 to 1% by mass with respect to the molded product. More preferred. Only one type of release agent may be used, or two or more types may be included. When 2 or more types are included, the total amount is preferably within the above range. By setting the content of the release agent in the above range, it is possible to suppress degradation of hydrolysis resistance while maintaining sufficient release effect, and to effectively suppress mold contamination during injection molding. .

<Other additives>
In addition to the above, the molded article of the present invention may contain other additives that can be generally used for polyamide resins, as long as the gist of the present invention is not impaired. Examples of such other additives include resins other than polyamide resins, lubricants, stabilizers, flame retardants, fluorescent bleaching agents, plasticizers, antioxidants, ultraviolet absorbers, antistatic agents, fluidity improvers, etc. Is exemplified. The total content of other additives is preferably 5% by mass or less of the molded product. Details of these additives can be referred to the descriptions in JP 2011-57977 A and JP 2015-129244 A, and the contents thereof are incorporated in the present specification.
Examples of other resins include polyester resins, polyphenylene sulfide resins, polyphenylene ether resins, polycarbonate resins, polyarylate resins, phenol resins, and epoxy resins.

The polyamide resin composition constituting the molded article of the present invention is molded to a thickness of 1 mm, and has a moisture permeability coefficient of 3.0 g · mm / min after standing for 42 hours at 40 ° C. and 90% relative humidity. preferably day · ^{m 2} or less, and more preferably less ^{1.5g · mm / day · m 2} . The lower limit value of the moisture permeability coefficient is preferably 0 g · mm / day · m ² , but 0.2 g · mm / day · m ² or more is sufficiently practical. The moisture permeability coefficient is a value measured by the method described in the examples.
Even if the water absorption rate of the polyamide resin is low, it cannot be said that the moisture permeability coefficient is small. This is because the polyamide resin has a different water absorption rate and diffusion rate.

The molded article of the present invention can be applied to various storage containers having transparent members, electrical and electronic equipment parts, office automate (OA) equipment parts, home appliance parts, machine mechanism parts, vehicle mechanism parts, and the like. In particular, it is preferably used as a camera component. As a camera part, it is used as a barrel, a holder, or a housing. In particular, the molded product of the present invention is preferably used as a camera part of an in-vehicle camera.
When the molded article of the present invention is a camera part, the maximum length is preferably 15 to 40 mm. By adopting such a configuration, a camera component having a balance between performance and appearance can be obtained.
When the molded article of the present invention is a camera part, it is preferable that the member is derived from the polyamide resin composition, and the ratio of the member is 1 to 99% by mass. By adopting such a configuration, it is possible to obtain a molded product excellent in the weight reduction of the camera component and the balance of the strength of the camera component.
In particular, the molded product of the present invention is preferably an injection molded product. Of course, it goes without saying that the molded product of the present invention may be a molded product other than an injection molded product.

Next, the manufacturing method of the molded product of this invention is demonstrated.
The method for producing a molded article of the present invention comprises a semi-aromatic polyamide resin and a fiber having a number average fiber length of more than 300 μm, and the terminal aromatic group concentration of the semi-aromatic polyamide resin is higher than the terminal amino group concentration. Injection molding the resin composition. The details of the semi-aromatic polyamide resin, fiber and the like are the same as described above.
The temperature during injection molding is preferably 260 to 300 ° C.
In the present invention, the method for producing the polyamide resin composition is not particularly defined, and a wide variety of known methods for producing a thermoplastic resin composition can be employed. Specifically, each component is mixed in advance using various mixers such as a tumbler and a Henschel mixer, and then melt kneaded with a Banbury mixer, roll, Brabender, single screw extruder, twin screw extruder, kneader, etc. Thus, a polyamide resin composition can be produced.

Also, for example, the polyamide resin composition can be produced without mixing each component in advance, or by mixing only a part of the components in advance, supplying the mixture to an extruder using a feeder, and melt-kneading the mixture. .
Furthermore, for example, a resin composition obtained by mixing some components in advance, supplying them to an extruder and melt-kneading is used as a master batch, and this master batch is mixed with the remaining components again and melt-kneaded. A polyamide resin composition can also be produced.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

<Semi-aromatic polyamide resin>
(Synthesis of polyamide (MXD6))
A semi-aromatic compound obtained by polycondensation of metaxylylenediamine and adipic acid according to the description in paragraph 0038 of JP2011-140620A, having a terminal amino group concentration of 40 μeq / g and a terminal carboxyl group concentration of 90 μeq / g A polyamide resin was synthesized. The ratio of the terminal amino group concentration to the terminal carboxyl group concentration ([NH ₂ ] / [COOH]) was 0.44. The obtained semi-aromatic polyamide resin is referred to as “MXD6”.

(Synthesis of polyamide (MP6-1))
According to the description in Example 2 of Japanese Patent No. 5218705, metaxylylenediamine, paraxylylenediamine, and adipic acid were polycondensed, and the terminal carboxyl group concentration ([COOH]) was 95 μeq / g, and the terminal amino group concentration. A semi-aromatic polyamide resin having a [[NH ₂ ]] of 45 μeq / g was synthesized ([NH ₂ ] / [COOH] = 0.47).

(Synthesis of polyamide (MP6-2))
In a reaction vessel equipped with a stirrer, a partial condenser, a full condenser, a thermometer, a dropping funnel and a nitrogen introduction tube, and a strand die, 878.4 g (60 mol) of adipic acid precisely weighed, sodium hypophosphite monohydrate Product (NaH ₂ PO ₂ .H ₂ O) 3.105 g (phosphorus atom concentration in the polyamide resin is 50 mass ppm) and 1.61 g of sodium acetate are sufficiently substituted with nitrogen, and then nitrogen is reduced to an internal pressure of 0.4 MPa. The mixture was heated to 170 ° C. with stirring and further stirring in a small amount of nitrogen. The molar ratio of sodium hypophosphite monohydrate / sodium acetate was 0.67.
To this, 8,335 g (61 mol) of a mixed diamine of 7: 3 (molar ratio) of metaxylylenediamine and paraxylylenediamine was added dropwise with stirring, and the inside of the system was continuously removed while removing the condensed water produced. The temperature was raised to. After completion of the dropwise addition of the mixed xylylenediamine, the melt polymerization reaction was continued for 20 minutes at an internal temperature of 260 ° C. Subsequently, the internal pressure was returned to atmospheric pressure at a rate of 0.01 MPa per minute.
Thereafter, the inside of the system was again pressurized with nitrogen, the polymer was taken out from the strand die, and pelletized to obtain about 24 kg of polyamide resin (MP6-2). The obtained pellets were dried with dehumidified air at 80 ° C. (dew point −40 ° C.) for 1 hour. The obtained MP6-2 had a terminal carboxyl group concentration ([COOH]) of 37 μeq / g and a terminal amino group concentration ([NH ₂ ]) of 89 μeq / g.

<End group concentration>
The terminal amino group concentration was measured by dissolving 0.5 g of semi-aromatic polyamide resin in 30 mL of phenol / methanol (4: 1 by volume) with stirring at 20-30 ° C. and titrating with 0.01 N hydrochloric acid. did. As for the terminal carboxyl group concentration, 0.1 g of semi-aromatic polyamide resin was dissolved in 30 mL of benzyl alcohol at 200 ° C., and 0.1 mL of phenol red solution was added in the range of 160 ° C. to 165 ° C. The solution was titrated with a titration solution (KOH concentration 0.01 mol / L) in which 0.132 g of KOH was dissolved in 200 mL of benzyl alcohol, and when the color change became yellow to red and the color change disappeared. Calculation was made by setting the end point.
The unit of the end group concentration is μ equivalent / g.

<Fiber>
Glass fiber: manufactured by Nippon Electric Glass Co., Ltd., ECS03T-296GH, average fiber length of 3.0 mm, short fiber diameter of 10.0 μm

<Black colorant>
Carbon black (Mitsubishi Chemical Corporation MA600B)
<Talc>
Micron White # 5000S: Hayashi Kasei Co., Ltd. <release agent>
Light Amide WH255: Kyoeisha Chemical Co., Ltd.

Example 1
After the semi-aromatic polyamide resin, talc, release agent and black colorant were weighed and dry blended so that the final composition was as shown in Table 1 below, a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., TEM26SS) was fed from the screw root using a twin screw cassette weighing feeder (manufactured by Kubota Corporation, CE-W-1-MP). About a black coloring agent, it injected | thrown-in after forming into a masterbatch using a part of semi-aromatic polyamide resin within the amount range. Glass fiber is fed into the above-mentioned twin screw extruder from the side of the extruder using a vibrating cassette weighing feeder (manufactured by Kubota Corporation, CE-V-1B-MP), and melt kneaded with resin components and the like. A pellet (polyamide resin composition) was obtained. The temperature setting of the extruder was 280 ° C.

<Measurement of moisture permeability coefficient>
A test piece having a thickness of 100 mm × 100 mm × 1 mm was injection molded at a cylinder temperature of 280 ° C. and a mold surface temperature of 135 ° C. using NEX80III-9E manufactured by Nissei Plastic Industry Co., Ltd. using the pellets obtained above.
Next, as shown in FIG. 1, 25 g of calcium chloride particles 12 was placed inside an aluminum cylindrical cup 11 having an inner diameter of 67 mm and an inner height of 80 mm. The test piece 13 was sealed at a position of 50 mm from the inner bottom surface of the cup, and allowed to stand for 42 hours in an atmosphere of 40 ° C. and a relative humidity of 90%. The mass of the calcium chloride particles was measured, and the water permeation coefficient was calculated by taking the difference (increase) from that before standing as the amount of permeated water.
The unit of the moisture permeability coefficient is g · mm / day · m ² .

<Bending strength>
After the pellets were dried at 120 ° C. for 4 hours, using a FANUC injection molding machine (100T), molding with a cylinder temperature of 280 ° C. and a mold surface temperature of 135 ° C. was performed with a thickness of 100 mm × 100 mm × 2 mm. The product was injection molded. The molding conditions were such that about 95% of the cavities were filled in about 0.5 seconds, and the holding pressure was set to about 80% of the VP switching pressure for 10 seconds.
The bending strength of the obtained molded product was measured according to ISO-178 standard. The unit of bending strength is MPa.

Example 2
In Example 1, the semiaromatic polyamide resin was changed to MP6-1, and the others were performed in the same manner.

Comparative Example 1
In Example 1, the glass fiber was changed to an equal amount of glass flake (Nippon Sheet Glass Co., Ltd. glass flake REF-015 average thickness 5 μm, average particle size 15 μm), and the others were performed in the same manner.

Comparative Example 2
In Example 2, the semiaromatic polyamide resin was changed to MP6-2, and the others were performed in the same manner.

  As is clear from the above results, the molded product of the present invention was a molded product having excellent mechanical strength.

11 Cup 12 Calcium chloride particles 13 Test piece

Claims (15)

A molded article molded from a polyamide resin composition, comprising a semi-aromatic polyamide resin and fibers having a number average fiber length of more than 300 μm, wherein the semi-aromatic polyamide resin has a terminal carboxyl group concentration higher than a terminal amino group concentration. The molded article according to claim 1, wherein the fiber is at least one selected from carbon fiber and glass fiber. The molded article according to claim 1 or 2, wherein the fiber is treated with at least one of a surface treatment agent and a sizing agent. The molded article according to any one of claims 1 to 3, wherein the number average fiber length of the fibers is 1.0 mm to 6.0 mm. The molded article according to any one of claims 1 to 4, wherein a difference between the terminal carboxyl group concentration and the terminal amino group concentration is 40 to 100 µequivalent / g. The semi-aromatic polyamide resin is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and 70 of the structural unit derived from dicarboxylic acid. The molded article according to any one of claims 1 to 5, wherein at least mol% is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The semi-aromatic polyamide resin is composed of a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and 70 of the structural unit derived from dicarboxylic acid. The molded article according to any one of claims 1 to 5, wherein at least mol% is derived from adipic acid. Furthermore, the molded article of any one of Claims 1-7 containing a black coloring agent. Furthermore, the molded article of any one of Claims 1-8 containing a talc. Furthermore, black colorant and a talc are included, The mass ratio (black colorant / talc) of a black colorant and a talc in the said molded article is 1.5-2.5 any one of Claims 1-7. The molded article according to item. The molded article according to any one of claims 1 to 10, which is an injection molded article. The molded article according to any one of claims 1 to 11, which is a camera part. The molded product according to claim 12, wherein the maximum length of the camera component is 15 to 40 mm. The molded article according to claim 12 or 13, wherein the camera component includes a member derived from the polyamide resin composition, and a ratio of the member is 1 to 99% by mass. Including injection molding a semi-aromatic polyamide resin and a polyamide resin composition containing fibers having a number average fiber length of more than 300 μm, wherein the terminal aromatic group concentration of the semi-aromatic polyamide resin is higher than the terminal amino group concentration The manufacturing method of the molded article of any one of Claims 1-14.